Car stays in open loop.
#1
Car stays in open loop.
I just fully rebuilt my engine. After it's first start up, I noticed the car idles rich in the 12s even after it's fully warm. I have a rogue logger and my tps and dme temp sensor appear fine. I am also fairly confident I have no vac leaks and my idle is reset properly and my fuel pressure is set (adjustable fpr). My idle stabilizer seems to be working as it should. I notice in the logger that it's not going into closed loop once warm at idle. I ordered a new O2 sensor and should get it soon. But is there any other things that might cause the car to stay in open loop constantly that I can check in the mean time? The car is running m tune, LR version. While in open loop at warm idle I can adjust the fqs to - 11% fuel and get the car closer to 13.5 - 14.0. shouldn't my open loop be a little closer to 14.7 at idle without pulling so much fuel? I know closed loop would bring it in but the transition from open to closed would have to compensate more to do so?
Last edited by mahoney944; 10-01-2018 at 05:02 PM.
#2
Rennlist Member
Do you have multiple maps on your m tune set up? I know with my Vitesse chipboard, I have the choice between pump gas, race gas, e85, more timing/fuel, less, etc. One of my E85 maps, for example, adds about 30% extra fuel and disables closed loop operation. If I ran that map on pump gas, it would behave much like you describe...
#3
Do you have multiple maps on your m tune set up? I know with my Vitesse chipboard, I have the choice between pump gas, race gas, e85, more timing/fuel, less, etc. One of my E85 maps, for example, adds about 30% extra fuel and disables closed loop operation. If I ran that map on pump gas, it would behave much like you describe...
#4
Also could be a bad MAP sensor.
#5
I have a new klr with only about 10 miles on it so I'll look past that for now. I have an extra map sensor I can try, which I will. The logger shows what position the tps is in and its spot on from what I can tell.
#6
Could be. What happens when you unplug it and/or jumper the diagnostic port?
Also, can you see on the logger if the DME is in WOT mode by mistake? Crazy Eddie's car had a cracked solder joint in the KLR that would cause the car to move to the WOT maps at idle and part throttle, which made it run rich and took it out of closed loop mode. A bad TPS could do the same...
Also, can you see on the logger if the DME is in WOT mode by mistake? Crazy Eddie's car had a cracked solder joint in the KLR that would cause the car to move to the WOT maps at idle and part throttle, which made it run rich and took it out of closed loop mode. A bad TPS could do the same...
#7
Three Wheelin'
There seems to be a common perception on Internet forums that "open loop" automatically means "rich mixture." This is not 100% the case. Open loop means that the DME is ignoring the signal from the oxygen sensor and running solely off the base map in the DME. During cold-start enrichment and in the WOT map (>66% throttle), this happens to be a richer mixture for obvious reasons. But at idle and cruise, a perfectly running 951 with no vacuum leaks or other defects should be running right around 14:1, even in open loop. If your 951's idle changes drastically when the O2 sensor is unplugged, your base mixture is not correct.
Something is making Mahoney's DME stay in open loop, but that doesn't automatically mean that the same issue is causing the rich mixture. You have 80# fuel injectors---I have the 80# Deka injectors in my otherwise stock engine running VEMS, and the injector duty cycle is only 2% at idle with a Bosch 3 bar fuel pressure regulator and 044 fuel pump. What did you set your fuel pressure to? Have you verified the setting with a gauge? What about your MAF/MAP readings?
Something is making Mahoney's DME stay in open loop, but that doesn't automatically mean that the same issue is causing the rich mixture. You have 80# fuel injectors---I have the 80# Deka injectors in my otherwise stock engine running VEMS, and the injector duty cycle is only 2% at idle with a Bosch 3 bar fuel pressure regulator and 044 fuel pump. What did you set your fuel pressure to? Have you verified the setting with a gauge? What about your MAF/MAP readings?
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#8
Fuel is set to 43psi. I tried two different ways of setting it with no difference. First way, I jumped the fuel pump to stay on and disconnected the vac line, then set it. I also tried removing the vac line with the engine idling then set it. Both methods we're fairly similar settings. want to say the voltage was around 0.88 going off memory. I'd have to double check though.
Last edited by mahoney944; 10-02-2018 at 08:44 PM.
#9
What functions does the klr chip serve? I can't remember what chip is in there now.... I'm thinking its a LR 951 max chip. Not sure what chip m tune needs or if it matters on the klr side of things. That might be a question for Josh.
#10
Rennlist Member
It's also possible that your car is just running so rich that it is outside the range of what your closed-loop system can make up for. .88v at idle is high for other systems, though don't know about m-tune. MAF Grounds good? I'd be temped to check the WOT signal by confirming there is 5v at terminal B (1 o'clock) on the diagnostic port under the hood when idling. The WOT maps are ON if terminal B shows ground (zero volts). Also, might as well check blink codes while you're there. Did all of the same components work well and give you a good AFR before the rebuild, or is it possible you've mixed and matched parts that don't like each other?
#12
Got the new O2 sensor and started the car up. As soon as I hit 150 degrees the car went into closed loop and idled 14.7. So that's sorted now. I do however think it's odd that the open loop seems too rich all around, if I jump the isv on the diagnostic port my fuel ratios go into the 12s at idle. I can lean it out with the fqs but that seems like a band aid to possibly another issue. Everything was just replaced on the engine, funny enough besides the oxygen sensor since I bought it slightly before tear down. It was a complete bare block up rebuild and I replaced all the rubber hoses and clamps, fixed any connectors that showed any wear etc. I'm fairly confident there's no vac leaks unless there is a brake booster issue I'm unaware of...any good tests for that?
#13
It's also possible that your car is just running so rich that it is outside the range of what your closed-loop system can make up for. .88v at idle is high for other systems, though don't know about m-tune. MAF Grounds good? I'd be temped to check the WOT signal by confirming there is 5v at terminal B (1 o'clock) on the diagnostic port under the hood when idling. The WOT maps are ON if terminal B shows ground (zero volts). Also, might as well check blink codes while you're there. Did all of the same components work well and give you a good AFR before the rebuild, or is it possible you've mixed and matched parts that don't like each other?
#14
Three Wheelin'
Got the new O2 sensor and started the car up. As soon as I hit 150 degrees the car went into closed loop and idled 14.7. So that's sorted now. I do however think it's odd that the open loop seems too rich all around, if I jump the isv on the diagnostic port my fuel ratios go into the 12s at idle. I can lean it out with the fqs but that seems like a band aid to possibly another issue. Everything was just replaced on the engine, funny enough besides the oxygen sensor since I bought it slightly before tear down. It was a complete bare block up rebuild and I replaced all the rubber hoses and clamps, fixed any connectors that showed any wear etc. I'm fairly confident there's no vac leaks unless there is a brake booster issue I'm unaware of...any good tests for that?
It seems that your tune/configuration results in a rich mixture at idle. This might not be too much of an issue, so before pulling your hair out trying to figure out what is causing it, check out your general tune in open loop (disconnect O2 sensor) at light load and cruise conditions and see where the mixture is. If it is in the 13.5-14:1 range, then it should be good and the closed-loop feedback will take care of the rest. If it is in the 12s at this range, then it is too rich all around and might not run very well with the O2 sensor feedback constantly making large corrections to the injector pulsewidth. In that case I would work on figuring out what is causing the rich running, whether it is a sensor out of calibration or simply the tune itself.
#15
OK, the "open loop" that you mention at the beginning of the post refers to the DME ignoring the O2 sensor signal. When you jumper the pins under the hood, that simply bypasses the idle control valve---that would be a form of "open loop," but I wouldn't refer to it as that because it causes confusion. When you bypass the ICV, the idle speed/mixture is solely based on the idle adjustment screw in the throttle body and the mixture adjustment in the stock AFM (or in the case of the Rogue setup, whatever the MAF/chipset is calibrated to at that airflow setting).
It seems that your tune/configuration results in a rich mixture at idle. This might not be too much of an issue, so before pulling your hair out trying to figure out what is causing it, check out your general tune in open loop (disconnect O2 sensor) at light load and cruise conditions and see where the mixture is. If it is in the 13.5-14:1 range, then it should be good and the closed-loop feedback will take care of the rest. If it is in the 12s at this range, then it is too rich all around and might not run very well with the O2 sensor feedback constantly making large corrections to the injector pulsewidth. In that case I would work on figuring out what is causing the rich running, whether it is a sensor out of calibration or simply the tune itself.
It seems that your tune/configuration results in a rich mixture at idle. This might not be too much of an issue, so before pulling your hair out trying to figure out what is causing it, check out your general tune in open loop (disconnect O2 sensor) at light load and cruise conditions and see where the mixture is. If it is in the 13.5-14:1 range, then it should be good and the closed-loop feedback will take care of the rest. If it is in the 12s at this range, then it is too rich all around and might not run very well with the O2 sensor feedback constantly making large corrections to the injector pulsewidth. In that case I would work on figuring out what is causing the rich running, whether it is a sensor out of calibration or simply the tune itself.